The NFL's vice president of officiating addressed a number of debatable calls Wednesday after another controversial weekend, most notably saying that Vikings tailback Adrian Peterson should have been penalized 15 yards for removing his helmet on the field Sunday during Minnesota's 28-27 victory over Green Bay.

Mike Pereira also said on NFL Sirius Radio that officials correctly called intentional grounding against Packers quarterback Aaron Rodgers earlier in that game. Finally, Pereira defended the actions of officials at the end of Monday night's game between Arizona and San Francisco.

As for Peterson, Pereira said he violated the NFL's rules prohibiting the removal of helmets when not in the bench area or during a timeout. Peterson removed his helmet at least four times during the game, but Pereira specifically pointed out Peterson's actions after scoring the game-winning touchdown with 2:22 remaining.

"I can't figure out why anything wasn't done about that," Pereira said, "but I will say this: It frustrates me that we didn't do anything about that. You can't take your helmet off either to argue a call or to celebrate. If you're in a timeout period or a measurement or a challenge, there are times when you can take your helmet off on the field. Or when you're nearing your team area when you approach the bench.

"But when you score like that, when you remove your helmet, you should be flagged."

Pereira, however, said referee Alberto Riveron made the right call when he whistled Rodgers for intentional grounding in the end zone during the second quarter, resulting in a safety. Rodgers flipped a sidearm pass in the direction of tight end Tory Humphrey, but Pereira doubted that Rodgers knew Humphrey was there.

"[We] have looked at so many of these plays where you get the unnatural throwing motion where the QB is just trying to dump the ball, whether it's behind his back or whether it's flicking it underhand just before he hits the ground when he has no idea who he might be throwing it to.

"Here's the notion to me: When you're going to be on the run like that and you are just totally dumping it either before you're getting tackled for a safety ... that unnatural act of dumping the ball when you're about to be tackled ... [If] you're going to do that, you'd better get it all the way back to the line of scrimmage or you'd better get it to the feet of the receiver. "

Finally, Pereira said that referee Tony Corrente followed "normal procedures" at the end of Monday night's game. On the game's final play, officials moved the line of scrimmage from the 1-yard line to the 2½-yard line based on a review. San Francisco coaches have said they were unaware of the change at the time.

"You know, all I really care is that we followed normal procedures and that's what we did," Pereira said. "We tried to anticipate, before even the decision was made, to make sure that the 49ers understood that no matter what decision was made, unless we ruled a touchdown, that the clock was going to start on the ready, that it was going to start on Tony Corrente's signal. We wanted to make sure they did not get caught in a situation where they would be in the huddle and we were starting the clock. So that we did.

"Now, Tony's announcement is the normal procedure. When he came out and made the announcement that the ball was going to be spotted at the 2½-yard line, which is where it was when [Frank] Gore first went down, then we had to get to our positions because the ball was going to be put down and the snap's going to come ... It's the same thing that we have always done and it was no different in San Francisco than it would have been anywhere else."